Refrigerator



L,LBRONAUGHETAL REFRIGERATOR Filed Feb. 16, 1931 /7 7- TUR/v5 5/ POTT f-R //\//5/\/ TERE L. J. BRONAUGH latented Oct. 6, 1936 Urraof srarss PACE land, Oreg.; said Bronaugh assignor Potter tosaid ApplicationFebruary 16, 1931, Serial No. 516,032

2l Claims. icl. 62-116) cally defrosted is unsuitable for thepreservation This invention relates generally to the art ofrefrigeration, and particularly to a. new form' of refrigerator.

The main object of this invention is the design 5 of a refrigeratorwhich will make it possible at 'one and the Sametime and over long orshort periods of time to perform several highly desirable tasks, namelyto form ice or freeze desserts quickly, to provide cold storage forfrozenmeat and foo'd stuffs, and to provide storage for food at ytemperatures above freezing.

.'I'he second object is to construct a cabinet in which the ice-makingor freezing unit is thermally insulated from the food storagedepartment.

.l5 The third object is the constructionof a refrigerator which is not acompromise'between a quick freezing refrigerator and one whichis idealfor food storing, but which will possess both of these properties inmaximum quantities.

The fourth object is to provide a refrigerator having its heat pumpingaction' controllable by food compartment temperatures and in which theeiilciency of the freezing unit will be increased as the rate of heatpumping from the food department increases. i The vfth object is tosecure the utmost sim-A all defrosting and objectionable drying out ofthe foods.

The eighth object is to make it possible for the 40 householder tovutilize all of the advantages obtainable from varying degrees ofrefrigeration heretofore only possible in large commercial plants.Before entering into a description of this invention it must beunderstood that while mechanical refrigeration has many advantages overthe ice box used by our ancestors, it has many limitations which aregreatly magnified in the smaller sizesI of refrigerating units,especially of the type used in the home. These limitations andrequirements have been increased rather than decreased by the advent ofthe use of frozen food stuffs,

which render it imperative that the frozen food remains frozen until itis prepared for use.

Obviously, a refrigerator which must be periodiof this class of food. t

Again, there are, generally speaking, two classes of food which are putinto a refrigerator; rst, food requiring merely to be kept cool-that is,above freezing, and in most cases having a relatively high rate ofevaporation.` Second, food having a relatively low rate of evaporationand which should be maintained at temperatures Well below freezing. Inaddition to this, comes the l0 ever increasing demand for the ability toform ice Aand freeze desserts quickly.

It follows that the designer of a refrigerating machine soon findshimself compromising be@ tween a quick freezing machine and one which isl5 best adapted for the storage of food. If the temperature of the foodstorage compartment falls too low as the result of an attempt to providequick freezing' the consequence is a rapid drying out of the'food. Tooffset this certain manu,- 2a,v

facturers providea cover for the food to prevent its drying out andimpose'upon the user the necessity of frequentlyvadjusting the controlsto obtain f the kind of refrigeration desired. It is easily seen that anadjustment of controls to suit varying 25 conditions (several of whichmay exist at the same time) does not 'solve the problem. Intherefrigerator about to be described no adjustment of controls isnecessary.-

These, and other objects, will become more ap- 30 parent from thespecification following as illustrated in the accompanying drawing, inwhich:

Fig. l is a'vertical section taken along the line 'i-i in Fig. 2.

Fig. 2 is a vertical section taken along the line 35 2-2 in Fig. l; I lFig. 3 is a perspective view of the cabinet.

Fig. 4 is a sectionl taken along the line t--t in Fig-2.

Similar lnumbers of reference refer to similar 40 parts throughout theseveral views. p f

Referring in detail to the drawing, there is shown a cabinet having fourseparate and distinct com partments contained withinan outer casing Iii.These' consist of a pump room il a freezing com- 45 partment I2, a coldstorage compartment i3 and a food storage compartment it. The pump roomli contains any desirable form of heat pumping unit which, in thisinstance, includes a compressor l5 which is belt driven by a motor it.There is 50 also provided the usual receiver il and condenser te. .i i

The freezing compartment it is preferably a brine tank and includessuitable freezing trays i9. Adjacent to the freezing compartment i2 isac'old 35 Gil one or more shelves 20. Heat is permitted to flow freelyfrom the cold storage compartment I3 throughthe wall 2l to the freezingcompartment I2, butthe compartments I2 and I3 may not draw heat from anyother portion oi' the refrigerator. The freezing compartment or brinetank, contains an expansion coil 22 which will be referred to as afreezing coil, and which is provided with the expansion valve 23. Thecoil 22 draws refrigerant from the receiver I1 through the high pressurerefrigerant line 24. The food storage compartment I4 is provided with acooling coil 25 which draws refrigerant from the discharge of thefreezing coil 22 and returns same through the pipe 26 to the compressorI5. l

The compartment I4 may have any number of divisions and shelves 21 andcontains a drip collecting shelf 28 by means of which condensed moisturefrom the cooling coil 25 is collected and drained through an outlet.29,either into a container 30 (as shown) or into a waste pipe. The foodstorage compartment I4 contains a temperature-actuated motor controllingswitch 3l which is placed in the motor circuit 32 and is set to operatethe compressor I5 whenever the temperature of the food storagecompartment rises above the desired temperature, which, in this case,will be assumed to be forty degrees. The expansion valve 23 is set topermit av flow of refrigerant into the freezing coil 22, which willprovide a temperature approximating zero, while the temperature in thecold storage compartment I3 will be in the neighborhood of twentydegrees. y

'Ihese relative values are of course dependent upon the variouscontrolling factors and are given only Ito permit a clearerunderstanding of the in- `vention and the objects attained thereby. Anysuitable insulating material 33 is employed in the construction of thecabinet, and the compartment I4, and combined'compartments I2 and I3 areprovided with doors 34 and 35 packed with insulation material.

The requisite 'difference of temperature between thecooling compartmentI4 and the cold storage compartment I3, can be maintained with thegreatest economic efficiency -by not only providing a proper ratio 'ofthe cooling elements for said compartments, but also by providing aproper relation of the insulation of theA two compartments. It will beunderstood that there is no such thing as a perfect heat insulator andthat a certain amount of heat is always flowing into a refrigeratorcompartment frcmthe surrounding atmosphere (provided, of course, thatthe surrounding atmosphere is Warmer vthan that of the refrigeratorcompartment). A heat insulator may thus be more properly termed a heatiinpedance because all it does is to retard the ow of heat and the rateof heat flow through a heat insulator of given quality and thicknessdepends upon the temperature head. Since very low temperatures are to bemaintained in compartments I2 and I3 it is important that they bethoroughly heat insulated. In other words, theheavier the insulation thebetter and the only limitation to the eiiiciency of such insulation isthat imposed by questions of bulk, and expense. As shown in the drawing,compartmentsY I2 and I3 are 'separated from the outside atmosphere bythick rear and side walls 38 and also by a thick door 35 so that theheat flow into said compartments is reduced to a minimum. Since thechamber I I under the compartments I2 and I3 contains the apparatus forpumping heat out of the refrigerator, this compartment would naturallybe warmer than the outside atmosphere and consequently a wall 33 isprovided which is even thick'er than the walls 38 to insulate thechambers against heat pumped into and generated in the compartment I I.The temperature drop between the cooling compartment I4 and compartmentsI2 and I3 is comparatively much smaller and hence a thinner wall 40furnishes sumcient resistance to heat flow into compartments I2'and I3out of compartment I4. The walls 4I and door 34 separating the coolingcompartment I4 from the outside atmosphere are thinner than the walls 38and door 35, as shown. This difference of wall thickness is provided notas a measure of economy but because it is desired to maintain a highertemperature in compartment I4 than in compartments I2 and I3 bypermitting a greater heat flow into compartment I4.

As indicated above it makes no difference how low the temperature fallsin chambers I2 and I3, but the range of temperatures permissible incompartment I4 is more critical. Foods kept in compartment I4 must lnotbe frozen and the moisture saturation point of the air in compartment I4should not be lowered to such an extent as to dry out the foods; henceit is important to hold the temperature in said compartment well abovethe freezing point and yet low enough to prevent the food therein fromspoiling. We have found that a temperature of about 40 Fahrenheit isvery satisfactory under most conditions; but some other normaltemperature may be selected provided it is above the freezing point.Whatever the temperature selected, it is obvious that it should bemaintained without any great degree of variation and'for this reason thecontrol of the heat pumping system is preferably made to depend upon thetemperature in the chamber I4 and the thermostat3l is placed in chamberI4 rather than either of the other chambers. If the insulation ofchamber I4 were as heavy as that of the other chambers the temperaturein the compartment I4 might remain for a long period unvaried and in themeantime the temperature might be raised considerably in chambers I3 andI2, by opening the door 35 or by introducing warm foods therein. withoutin the least affecting the thermostat 3l and hence without operating theheat pumping unit. Thus the temperature ratio between the severalcompartments would be disturbed and could not be restored until the heat.pumping unit was restarted. Since, however, the insulation separatingchamber I4 from the outside atmosphere is so proportioned that the rateoi ambient heat flow into chamber I4 is greater than into cham-V bers I2and I3, the intervals between operations of the heat pumping unit isreduced and thus more frequently are the relative temperatures o! theseveral chambersreestablished. It will be understood, of course, thatbecause of the series connection of the cooling elements the heat willbe pumped out of compartments I2 and I3 through the cooling element 25so that said compartments must be reduced to the desired temperaturebefore the compartment I4 will be chilled sufliciently for thethermostat 3I to stop the operationof the heat pumping plant.

While the thermostat 3l controls the temperature of the compartment I4the setting of the expansion valve 23 controls the temperature ofcompartments I2 and I3. `As the expansion Y mated' entireltr.v butalsothe.

therein, will cool compartment I 4. Thus, by our system the compartmentsI2 and I3 must first be cooled tominima fixed by the setting of theexpansion valve beforecompartment I6 can be lcooled to a minimum set bythe thermostat. This arrangement whereby onetemperature iscontrolled bya thermostat and anotherby an expension valve is a novel feature ofourinvention. By proportioning the insulation to offer greaterresistance to inflow of heat into the cooling com `pertinent; I4 thaninto the cold storage compartment I3, a more uniform temperature can beobtained in the latter compartment. Were the insulation of theA twochambers ofthe same heatresistant quality and thickness, the rate ofinflow into the cold storage compartmentwould be greater, by. reason ofthe greater temperature drop between the outside .atmosphere and thecold storage compartment than between the outside atmosphere and thecooling compartment. The heat pumping unit, after pulling down thetemperatures of the two compartments to their re-I spectivepredeterminedheat levels would then be stopped by actuation ofthethermostat in tlie cooling chamber. Thereafter, the temperature .inthe cold storage chamber would climb faster than that inthe coolingchamberbecause of the greater head of ambient heat impressed on theinsulationv of the cold storage chamber. Hence. there would be amarkedrise in temperature in the freezing compartment before thetemperature in the cooling compartment would rise sufficiently toactuate the thermostat. This difculty wc` have overcome byproportioningthe heat impedance of the walls tothe heat head they must oppose andwhile suchproportioning results in# cidentally in economy of material,it has for its primary object to maintain a more uniform tem perature inthe cold storage compartment as well as in the freezing compartmentwhichis thery mally connected therewith.

` From the foregomgtlt win be seein that there is provided .arefrigerator having a non-frosting food storage compartment in whichfood may beheld atv desirable' temperatures withoutundue evaporation.Secondly, that quick freezing for ice and desserts is ever available.Thirdly. that there is provided' uninterrupted cold storagev at freezingtemperatures, and'lastly, that the necessity for regulating thecontrolfsystem is en tirely eliminated since awide range of temperaturesis provided simultaneously, and further..

that lnot only is the necessity for defrostinglelim- V v vaporation-"of"the food stuusis redueecto a minimum; j

'I'hearticles placed inthe cold lstorage compartment are those notgivingfon much moisture,-

cold storage compartment, yeither byrevaporation or by' opening the doorthereof. will be deposited ,i as snow rather.. thanas ice.V due tothelow temperature prevailing .in 'the compartment I3. In

other'worfds, there is noobjectionable f'ros'ting'inV the' cold storagecompartment. for -thereason above stated, and no frosting coolingcomf-Iand whatever moisture does find its way into the the freezing point.

is above freezing.- lThere may, of course, occur a slight amount. offrosting where the coolingv coil 25 enters the compartment I4.

Another factor of great value found in this arrangement resides in thefact that the more the cooling compartment is used the greater will bethe efficiency of the cold storage and freezing compartments. t

By arranging the compartments as illustrated with the cooling chamber I4which isthe one partme'nt since the temperature maintained there mostused, at the top of the cabinet, access may' l be had to thiscompartment without stooping, while-the intermediate compartments I2 andI3 are also elevated by placing them above the compartment II, so thatthe various food chambers are arranged to provide maximum convenience inactual service.

We claim:

1. A refrigerator consisting of a cabinet having formed therein acooling compartment, a combined freezing and cold storage compartmentthermally connected lto each other butl insulated from said coolingcompartment, means for pumping heat from all of said compartmentsthrough saidcooling compartment, and means for controlling the heatpumping action actuated by the temperature of said cooling compartment.

2. A self-contained refrigerator comprising a' cabinet having a coolingcompartment and a cold storage compartment below vthe coolingcompartment and thermally insulated therefrom and having also a freezingcompartment also thermally insulated from the cooling compartment but.thermally connected to the cold storage compartment and a pumpcompartmentbelow and thermally insulated from thecold storage andfreezing compartments, an'expansion line including in series a coil inthe freezing compartment and a coil "in the cooling compartment, saidcoils being proportioned to maintain a temperature above-freezing in thecooling compartment and a materially lower, temperaturel in the freezingcompartment,

a single expansion valve in the line-at the point of entrance the f intothe freezing compartment', a heat pumping unit in the pump compartmentfor circulating refrigerant through said 3. A household refrigeratorcomprising a cabinet formed with a freezing compartment, a cold storagecompartment thermally connected thereline, and thermally actuated meansin the cooling compartment for controlling the pumping unit.

with but separated therefrom by a continuous" partitlon, a coolingcompartment thermally insulated from the freezing andv cold'storagecompartments and insulatedv against loss of moisture thereinto, andmeans for maintaining the freezing and cold'storage compartments at atemperature well-below the freezing point and thecooling compartmentat"` a predetermined temperature above v4. A refrigeratoncomprising a.cabinet formed i with twoI compartments and with heating insula-4tionseparating saidv compartments from each other and from the voutsideatmosphere, refriger ating means- .for abstracting heatfrom-.both of xthe compartments. insulation of p the compartments being adapted to odera higher resistanceto inflow of heat into one compartment than into theother,V and thermo-.sensitive'means in the" latten compartment forcontrolling said refriger' 5. -A'refrierawr eemprising afcabinet formenAwithfa; cooling compartment and a cold storage compartment, thermallyment to a lower temperature than that of the cooling compartment, thethermal-insulation of the compartments being rso relatively proportionedas to offer a greater resistance to inow of heat into the freezingcompartment than into the cooling compartment, and thermo-'sensitivemeans for controlling the refrigerating means, said thermo-sensitivemeans being located in the compartment into which there is the greaternor-` mal inow of heat.v

6. A refrigerator comprising a cabinet formed with a cooling compartmentand a freezing compartment thermally insulated from each other and.fromthe outside atmosphere, refrigerating means for cooling the freezingcompartment to a lower temperature than that of the cooling compartmentand thermo-sensitive means in the latter compartment for controllingsaid refrigerating means, the thermal insulation of the compartmentsbeing so relatively proportioned as to admit a greater inflow of heatinto the cooling compartment than into the freezing compartment.

7. A refrigerator comprising a cabinet formed with a cooling compartmentand a freezing compartment, said compartments being thermally insulatedfrom each other and from the outside atmosphere, means for pumping heatfrom the freezing compartment through the cooling compartment so as tolower the temperature of the former below that of the latter,.and acontroller for said means responsive to temperature conditions in thecooling compartment, the thermal insulation of the two compartmentsbeing relatively so proportioned as to offer a greater resistance toinflow of heat into the freezing compartment than into the coolingcompartment.

8. A refrigerator comprising a cabinet formed y with a 'coolingcompartment and a freezing compartment and a power plant compartment, aheat vpumping unit in the latter compartment, an expansion lineoperatively connected with said unit.

and extending sequentially through the freezing and coolingcompartments, a controller for said unit actuated by temperatures in thecooling compartment, the cabinet having outside walls ofinsulationmaterial and partition walls of insulation material betweenthe compartments, the insulating quality of the walls beingyindividuallyY proportioned to predetermined differences'of temperature on oppositesides thereof.

9. A refrigerator comprising a cabinet formed with a cooling compartmentand a freezing compartment and a power plant compartment, a heat pumpingunit in the latter compartment, an expansion line operatively connectedwith said unit and extending sequentially through the freezing andcooling compartments, `a controller for said unit actuated bytemperatures in the'cooling coml partment. the cabinet having outsidewalls of insulation material and partition walls of insulation materialbetween the compartments,'theinsulat ing quality of the walls beingindividually proportioned to predetermined differences of temperature onopposite. sides thereof. the cooling compartment being located above thefreezing compartment and the power plant compartment below the Vfreezingcompartment.

10. A refrigerator a cabinet formed i with a lcooling compartment and afreeling compartment.. said cots being insulated .from each other andfrom the outside atmosphere. hasi-expansion line passingthrough thefreising and cooling compartments, said line including a freezing coilin the freezing compartment and a non-frosting coil inthe coolingcompartment, an expansion valve in said line at its point of entranceinto the freezing compartment, means for forcing refrigerant throughsaid line, and a controller for said means actuated by temperatures inthe cooling compartment, the thermal insulation of the compartmentsbeing relatively so proportioned as to admit a greater inflow of heatinto the cooling compartment than into the freezing compartment.

11. A refrigerator comprising a cabinet formed with a coolingcompartment and' a freezing compartment thermally insulated from eachother and from the outside atmosphere, refrigerating means for coolingthe freezing compartment to a lower temperature than that of the coolingcompartment, and thermo-sensitive means in one of the compartments forcontrolling said refrigerating means, the thermal insulation of thecompartments being so relatively proportioned as to admit a greaterinflow of heat into the cooling compartment than into the freezingcompartment.

12. A household refrigerator comprising a cabinet having at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a refrigerating system constructed and arranged to coolone of said chambers far below the freezing point of water and the otherchamber above said freezing point, said system comprising an expander ineach chamber and apparatus within the cabinet for circulating a volatilefluid through such expanders, said fluid constituting the solerefrigerant thus circulated, said system also including meansconstructed and arranged to maintain the external surface temperature ofthe expander in the warmer chamber above said freezing point.

13. A household refrigerator comprising a cabinet having at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a refrigerating system constructed and arranged to coolone of said chambers far below the freezing point of water and the otherchamber above said freezing point, said system comprising an expander ineach chamber and apparatus withinthe cabinet for circulating a volatileuid through such expanders,.said-iluld v constituting the solerefrigerant thus circulated,

above said freezing point, said 'means comprising I instrumentalitiesfor maintaining `a wide temperature differential between the exteriorand the interior of the expander in the warmer chamber.

, 14. A household refrigerator comprising a cabinet having at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a compressor-condenser-expander system constructed andarranged to cool one of said 4chambers far below the freezing peint ofwater and the other chamber above said freezing point, said systemcomprisinga chilling element in each chamber and apparatus within thecabinet for circulating a volatile uld vthrough the chilling elements,said uid constituting the sole refrigerant in said system, said systemalso including means constructed and arranged to maintain the externalsurface of the chilling element in the above said freezing point.

aand" a compressor-condensen-exis pander system constructed and arrangedto cool one of said chambers far below the freezingpoint of water andthe other chamber above said freezing point, said system comprising anexpansion coil in each chamber and apparatus within the cabinet forcirculating a volatile fluid through such coils, said fluid constitutingthe sole refrigerant in said system, said system alsoincluding meansconstructed and arranged to maintain thek external surface of the coilin the warmer chamber above said freezing point.

v16. A household refrigerator comprising a cabinet lhaving at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a compressor-condenser-expander system constructed andarranged to cool one of said chambers far below the freezing point ofwater and the other chamber above said freezing point, said systemcomprising apair of chilling elements connected in series with one ofthe elements in each chamber and apparatus within the cabinet forcirculating a' volatile fluid through said elements, said fluidconstituting the sole refrigerant in said system, said system alsoincluding means constructed and arranged to maintain the externalsurface of the chilling element in the warmer chamber above .saidfreezing point.

17. A household refrigerator comprising a cabinet having at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a refrigerating system constructed and arranged to coolone of said chambers far below the freezing point of water and the otherchamber above said freezing point, said system comprising an expander ineach chamber and apparatus within the cabinet for circulating avolatilefiuid through such expanders, said fluid constituting the solerefrigerant thus circulated, said system also including control meansconstructed and arranged to maintain the humidity in the warmer chamberat a'relative value of at least 100 per cent at 32 degrees Fahrenheit.

18. A household refrigerator comprising a cabinet vhaving at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a compressor-condenserexpander system constructed andarranged to cool one of said chambers far below the freezing pointofwater and the other chamber above said freezing point, said systemcomprising a chilling element in each 'chamber and apparatus within thecabinet for circulating a volatile fluid through the chilling elements,said fluid constituting the sole refrigerant -in said system, saidsystem also including means constructed and arranged to.

maintain the humidity in the warmer chamber at a relative value of atleast 100 per cent at 32 degrees Fahrenheit.

19. A household refrigerator comprising a. cabinet having at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a compressor-condenser-expander system constructed andarranged to cool 'one of said chambers far below the freezing point solerefrigerant in said system, said system also including means constructedand arranged to maintain the external surface of lthe chilling elementin the warmer chamber above said freezing point; said means comprisinginstrumentalities for maintaining a wide temperature differentialbetween the exterior and the interior of the latter chilling element. Y

20. A household refrigerator comprising a cabinet having at least twofood chambers thermally insulated from each other and from the outsideatmosphere, and a compressor-condenser-expander system constructed andarranged to cool one of said chambers far below the freezing point ofwater and the other chamber above said freezing point, said systemcomprising an expansion coil in each chamber and apparatus within thecabinet for circulating a volatile fluid through such coils, said iiuid'constituting the sole refrigerant circulated through the coils,saidssystem 4also including means constructed and arranged to maintainthe external surface of the coil in the warmer chamber above saidfreezing point, said means comprising heat-absorbing fins formed on thelatter coil.

21. A household refrigerator comprising a cabinet having two foodchambers thermally in- 'sulated from each other and thel outsideatmosphere, refrigerating means in the cabinet ther- .mallyproportionedl to cool one of the chambers to asharp freezing temperaturewhile cooling frigerating means whenever the surface temperature of theexpander in the warmer chamber falls to a predetermined minimum abovethe freezing point of water and to restart the operation of therefrigerating means when said surface rises ,above a predeterminedmaximum.

LEWIS J. BRONAUGH. THOMAS 1.u POTTER.

